steamer wrote:

--Hey, anyone out there got an induction melting furnace? I'm
suddenly wondering if these are any good for melting aluminum, brass, etc;
i.e. do they depend on the material being melted having a magnetic field
to grab, or will nonferrous stuff melt just as well?


Will work ok for any metal as they rely on induced current. There are
problems for home use as they don't scale down very well.

1. As the size goes down the frequency has to go up for any efficiency (for
the same reason that mains frequency transformers use a laminated iron core
while a pc power supply at say 100KHz has to use a ferrite core). This
means for a few KW you need frequencys of a few KHz

2. The power factor (crudely watts/VA) is terrible. This basically requires
a big capacitor with either high voltage (10's of amps at 1000's of volts)
or high current (100's of amps at 100's of volts). The capacitor has the
full current flowing through it in the KHz range and these are not cheap.


--
regards
jc